What is a Gene? Gene = _______________________________ _______________________________________ Humans have approximately ____________ genes We have _____ copies of each gene (one on each chromosome we inherited from our ___________). Each gene has different forms . . . Allele - __________________________________ __________________________________________

Examples of Genes and Alleles in Pea Plants Gene – Seed Shape Alleles: _____________ _____________ Gene – seed color Gene – flower color

Chromosomes occur in pairs because offspring inherit one from each parent *We have 46 Chromosomes (23 pairs of chromosomes) Chromosomes are made of genes Circle one gene. What are the 2 alleles for that gene? *Each chromosome is made up of ________ that contains hundreds to thousands of __________. *HIERARCHY:

Dominant vs. Recessive NOT ALL ALLELES ARE EXPRESSED Some alleles are dominant, while others are recessive Description More Info Examples Dominant Alleles *These usually code for a protein so they are the “normal” form of a gene. Recessive *These usually code for a different protein, or deactivate the “normal” protein.

What happens when we change our DNA? Mutations: ____________________________ _______________________________________ Gene Mutations: _______________________ Types: _________________________________ Chromosomal Mutations: ________________  THESE CHANGES CAN AFFECT _________ MADE AND THEREFORE AFFECT YOUR ______________.

TYPES OF CHROMOSOMES Autosomes: ___________________________ Sex Chromosomes: ______________________ Karyotype: ____________________________ _______________________________________ Where do you look To determine the sex of this human? How do you know If it is normal or abnormal?

Karyotype Notation:

Significance of Mutations What Causes Mutations? There are two ways in which DNA can become mutated: 1. Mutations can be _________. Parent to child 2. Mutations can be _________. Environmental damage Mistakes when DNA is copied ________________failure of chromosomes to separate properly during Meiosis. What phase normally causes this? 1. MOST ARE _____________ Eye color Birth marks 2. SOME are _____________ Sickle Cell Anemia Down Syndrome 3. SOME are _____________ Sickle Cell Anemia to Malaria Immunity to HIV

PRACTICE WITH KARYOTYPES

MORE PRACTICE . . .